of the titles of this article is ambiguous. For further meanings see sleep (term clarifying).
Sleeping girl

the sleep is a condition of the peace of an animal or humans. Many signs of life differ from those of the awake condition. Pulse, Respiration rate and blood pressure drop and the brain activity change. In the sleep many motor and sensory nerve cells are blocked at least for the higher brain functions, so that the sleeping can hardly move in the sleep and notice hardly something. ThatThis function supports latches of the eyes during the sleep. With sufficient strong outside attractions (contact, bright light, loud noise) the sleeping wakes up however. The transitional phase from being awake to sleeping is the Prädormitium, ofSleep for being awake the Postdormitium. With the physiology as well as the disturbances of the Schlafes its own subsection of the medicine, the Somnologie ( sleep medicine) concerns itself.

Table of contents

physiological background

sleep introduction

at the sleep introduction are involved essentially three functional systems in the brain. By functional systems understandsone groups of nerve cells, which are regarded as matching, because they divide common tasks. To these nerve cell's groups, which control the sleep introduction, an area in the brain stem, the Formatio belongs reticularis, and two central brain areas: the Thalamus and that Hypothalamus. The Formatio reticularis is admits for its function as signal generator for awakeness (English. Arousal), and belongs therefore also to the ascending Reticulären so mentioned to activating system (ARAS). This attention or waking function practices the Formatio reticularisabout messenger materials (neurotransmitters) out, with those it the Thalamus (the gate to consciousness) excites. These messenger materials are Noradrenalin (WELL) and acetyl choline (oh). Within the Formatio reticularis there are further complex interconnecting and. A. with the Raphekernen. These exert a restraining influence on the noradrenergen systems with its transmitter Serotonin (5-HT) particularly when falling asleep.

On this occasion, i.e. falling asleep, these nerve cell's groups (one says also central areas) in the brain stem can braking over different ways upthe activity of the Thalamus influence. Here again another transmitter material is used, i.e. GABA. One can say thus that there are two ways, about the ascending Retikuläre activating system to the nonspecific Thalamus reached: directly for the activation and increasethe attention or indirectly over inserted restraining nerve cells (Interneurone) to the reduction of the attention and finally for sleep introduction.

Thus the ascending Retikuläre activating system is on the one hand responsible and on the other hand for the Wacheit for the sleep introduction. The brain goes alongits resources economically over. Besides the same central area in the brain stem affects braking the activity of nerve cell's groups in back Marks, which entails a general Schlaffheit of the musculature (atony): Humans are not tired only, but movealso less, when falling asleep in sitting the head falls forward.

Over the hypothalamus the brain experiences on detours that it is time for sleeping, because it became dark. This takes place over connections with the eye and/or. the Sehbahn. ThatHypothalamus produces now less from the transmitter histamine and a Peptid named Orexin. Orexin leads to increased attention.

Sleep maintenance and sleep phases

apart from the sleep introduction are caused also the maintenance and the completion of the Schlafes by nerve cell federations and functional systems.The sleep steered also in its further process neurophysiologically. For the maintenance of the Schlafes the brain (more exactly said functional systems in the brain) varies the depth of sleep in temporal distances. Deep sleep phases, in which the sleeping is to be waked up more with difficulty, change themselves alsoa less deep sleep off. If toward end of the Schlafes (thus usually after approximately 6-7 hours) these sleep phases change themselves in ever shorter distances, the sleeping becomes awake.

During the healthy Schlafes nerve cell federations begin themselves to synchronize. That means thatthey their Aktionspotenziale in a common clock fire. By deriving electric currents by means of a EEG these different rhythms can be measured and made visible. Depending upon depth of sleep and with it connected the characteristic sample leaves itself the sleep into differentStages divide. According to the frequency and amplitude these „internal rhythms “are differentiated the following stages and the pertinent waves, whereby the concrete organization of the sleep stages is however arbitrary I-IV:

  • Attention: Beta waves (14-60 cycles per second)
  • eases with closed eyes: Alpha waves (8-13 cycles per second)
  • stageI (more easily sleep, briefly after falling asleep): Thetawellen (4-7 cycles per second)
  • stage II: Thetawellen (4-7 cycles per second) and beta spindles. The latters are expression of communication between Thalamus and cerebral cortex
  • stage III: Delta waves (smaller than 4 cycles per second) and K-complexes
  • stage IV (deep sleep): Delta waves (smalleras 4 cycles per second)
  • rem sleep: desynchronisiertes EEG, beta waves

during the rem sleep are maximally relaxiert skeleton muscles, with exception of the eye musculature. Likewise it comes in this also phase called dream sleep to the increasethe blood pressure, the respiration and to Erektionen. In the stages I to IV the muscle tonus rises, parallel to it removes the activity of the brain. The stages I to IV with following rem sleep are repeated several marks per night.It is to be seen that the deep sleep phases decrease temporally and increases the rem phases. The stage IV is reached in the later process of the night no longer. Older humans do not reach very often the stage IV no more. Then changes alsothe sleep sample. Old humans sleep at night only few hours and sleep frequently on the day again until two hours. Babies sleep all day long, but in each case in short phases. With adults the sleep concentrates on a core time,usually at the night. A sleep cycle lasts approx. 90 minutes. This 90-Minuten-Zyklus continues also in the awake time and leads to phases of changing readiness to perform (Ultradiane Rhythmik).


Orexin (griech. orexis, „appetite “) works appetite-increasing. Also the Ncl.preopticus venterolateralis (VLPO, the Esszentrum of the brain) hypothalamus is involved in the sleep introduction. Lesions, D. h. Damages, in this part hypothalami lead to the Insomnie, the sleeplessness. The Ncl. suprachiasmaticus (SCN, S. o.) contains direct Afferenzenfrom the Retina. Here researchers assume the seat of the internal clock, neurons, which are responsible for the Circadiane Rhythmik. The SCN controls very strongly the activity of the Sympathikus. Over this vegetative system the SCN stimulates the releaseof Melatonin from the pineal gland. Melatonin is paid in the evening hours increased and contributes to the sleep introduction. The highest concentration is in the blood at 3 o'clock in the morning. Orexin (S. o.) works at its goal cells in the hypothalamus over onedetermined receptor, with which a disease picture is connected. Mutations of this receptor are made responsible for the Narkolepsie. In addition Orexin becomes as wake UP drug z. B. for fighter plane pilots uses. Dolphins (and some other organisms) have the possibility, with their hemispheres (brain halves) alternatingto sleep. That means that one half rests itself, while the other half takes over all necessary functions.

There are recommendations to let a falling asleep begin with sleep rituals: Evening prayer, „Schäfchen count “etc. help the psyche, over familiar thoughts on the peace toocome. From different circumstances however humans under sleeplessness, z suffer. B. in a reactive depression or because of the disturbance by pain. Under these circumstances sleeping drugs ( hypnotics) can be taken to assistance. Beside vegetable medicaments (z. B. Valerian)become in particular Antihistaminika, shorteffective Benzodiazepine (z. B. Brotizolam) as falling asleep means, centrallong effective Benzodiazepine (z. B. Nitrazepam and diazepam) as Durchschlafmittel as well as newer shorteffective sleeping drugs, like Zopiclon and Zolpidem, for the treatment of sleep disturbances assigned. Antihistaminika obtain theirEffects over an inhibition of the effect „of the waking hormone “histamine at its histamine receptors. Benzodiazepine, Zolpidem and Zopiclon work at the GABA receptors in the Thalamus. There they promote the restraining effect of this transmitter. In former times the very much spread bar bit urates become today due toan unfavorable use risk relationship (Suizid - potential and suppression of the rem sleep) practically no more than sleeping drugs does not use.

In the USA the hormone Melatonin, which is paid physiologically from the pineal gland, is sold to more and more as wonder drug and anti- Aging means. Admitsit is that Melatonin possesses sedating characteristics and in the evening hours ever more increases production and thereby a kind body-own sleeping drug represents it.

The body possesses further Mediatoren, which lead to increased sleep need. Thus develops with large metabolic achievements (manual labor)increases adenosine, which causes tiredness. Likewise Entzündungsmediatoren work such as Interleukin-1, which lead to increased sleep during a feverful illness.

Frequently it is necessary to overcome the sleep or the sleep need. Admits for its awakeness promoting and energizing effect is Koffein, that among other things in the coffee and in usually smaller concentration in genuine dte is contained. Koffein prevents the effect of adenosine. Paradoxically in the care coffee is sometimes used, in order to promote in and Durchschlafen. Particularly, helps older humans the Koffein, who waste of the respiration rate to fight [1].

Drugs of the type of the waking amines, like Amphetamin, Phenylethylamin, Ephedrin or Cathinon (from the Kath - sheets) work stimulating - with substantial side effects. Against forceful Schläfrigkeit,as it arises with Narkolepsie, one uses the Neurostimulans Modafinil.

Sleep duration and distribution

- individual fluctuations subjected - „the optimal “daily quantity to sleep for humans as well as its distribution over the day are scientifically disputed. After be enough thosenegative consequences of lack of sleep in the center of the research stood, turned out lately increasingly the obviously likewise unpleasant consequences of too much sleep in the field of vision. Seems to out-crystallize - according to large studies in the USA and in Japan -,that „the eight hours often specified are already too long on the day “and the optimum lies rather between six and seven hours, which corresponds also to the average sleep time in Germany (6 hours 59 minutes according to at the university Regensburg accomplishedStudy). A 75-jähriger Central European course-broke 25 years of its life with sleeping.

The individual sleep need of the adult varies for instance between 6 to 10 hours and follows approximately a normal distribution. Extreme ones arise with babies, those up to 16 hourssleep (distributed over the day), and with old humans, whose sleep need is smaller („senile bed escape “). According to opinion of the sleep researcher Peretz Lavie is to be proceeded from sleep-healthy humans, if these itself at a daily sleep duration from 4 to 12Hours probably feels.

It is of crucial importance that the individually differently minted sleep need is constitutionally given and therefore can not by wrongly understood „training “be switched off or at longer term not ignored, without the organism suffers damage. Who to humanswith increased sleep need belonged, therefore after possibility to it and adapt accordingly its behavior should stop its everyday life rhythm.

Further the phases of maximum and minimum efficiency are differently distributed depending upon type within a 24-Stunden-Tages. Simplifying can between a type of morning and a type of evening to be differentiated. The type of morning is already early in the morning fit and efficiently, the type of evening developed among other things as „Nachtschwärmer “at advanced evening time again a maximum of activity. In this connection also of owls and larks one speaks. In the year2005 those for a long time admitted genetic influences specified, which play here a role (Period3-Gen).

Supersleep is possible, because the hormone payment begins only after introducing the sleep. If one is waked up briefly after the beginning of the Schlafes, then one haspossibly REM - phase completed, possesses however not yet so a high hormone concentration that one falls asleep directly again.

With animals both the duration of the Schlafes varies altogether and the duration of the Rem Schlafes strongly from kind to kind:

Animal species sleepclosed in hours/ day portion that REM - phase at the sleep eye poetry clay/tone during
the Schlafes small bag mouse 20.1 16% both
brown bat 19.9 10% both closed
southern opossum 19.4 10% both closed
night ape 17.0 11% both closed
cat 13.2 26% both closed
Deaf 11.9 8% an eye sometimes openly
house chicken 11.8 10% an eye sometimes openly
Schimpanse 10.8 15% both closed
dog 10.7 29% both closed
Kaiserpinguin 10.5 13% an eye sometimes openly
fruit fly 10.0 0% no lids
duck 9.1 16% Eye sometimes openly
rabbit 8.7 14% both closed
pig 8.4 26% both closed
asiatic elephant 5.3 34% both closed
cow 4.0 19% both closed
horse 2.9 27% both closed
giraffe 1.9 21% both closed

source: New York Time - supplement that South German newspaper of 21. November 2005.

Hypotheses for the purpose of the sleep

the regenerativ hypothesis it means that sleep serves directly the recovery of the organs. It suggests that after the sleep many bodily functions work better than after a long awake phase. Howevernot all bodily functions are switched off also in the sleep: If someone turns the light on, then the eyes brightness announce; there is a noise, then the ears this announce.

The adaptive hypothesis means that sleep serves in principle not the recovery, but geneticallyconcerning its length is programmed, in order to receive an ecological equilibrium. Therefore and doses large robbery cats sleep approx. 18 hours on the day to recover not in order from the six awake hours to to avoid but around one „over feasting of “their hunting ground. ThatA chance is thus given to booty animals to multiply themselves and receive.

The calibration hypothesis means that sleep serves to bring the individual body systems back into an expiration rhythm. It can be assumed after sufficient sleep all organs andother bodily functions according to them imposed internal program to run begin, but over the day different speeds and irregularities experience. Sleep rekalibriert then quasi all systems again and sets it actually to zero.

The psychological hypothesis referson the fact that we process experiences of the awake phases in the sleep. The brain is cleaned with this processing of redundant information „“. Also the sleep helps to arrange new experiences and to process positive like negative experiences in the form of dreams. Psychologistestimate that humans after at long time without sufficient sleep is endangered, the insanity to purge.

Pathology of the Schlafes

lethal one family Insomnie is a deadly illness, with which the concerning are not able to sleep.
It actsthis illness around an extremely rare familiar left illness. For the illness a mutated Prionenprotein is responsible - gene. Most patients get sick to 40 between that. and 60. Lebensjahr. A heavy disturbance of the sleep awake rhythm of the patients, D is the center of attention.h., them suffer from heavy sleep disturbances. It is therefore accepted that the diseased changes take place particularly in the master brain, which as evolutionary old part of the brain the activity rhythm steers. The illness runs over seven to eighteen months and endsalways deadly. It was described for the first time in the year 1986 and their transferability was proven in the year 1995.

Sleep Apnoe is an illness, from which mostly over-weighty men in the middle age suffer. It is accepted that due to the reduced muscle tonus and the predominancethe respiratory system during sleeping to be compressed. Sometimes for this reason the gotten sick ones wake up some hundreds times at the night. The consequence is that deep sleep phases (stage III and IV, s.o.) as well as the rem sleep do not go through to at all shortenedbecomes. Often humans secondarily suffer from depressions.

With the Restless Legs syndrome („Wittmaack Ekbom syndrome “) the patients under unpleasant measurement feelings or movement urge in the legs (or arms) suffer, as soon as they come to the peace, so that they cannot fall asleep at night. The RLS is a neurological illness, those is very far common (5-10% of the population) and - also of the concerning themselves - often long time not as a cause of their sleep disturbances is recognized. The developing sleep withdrawal by the disturbed sleep phases cognitive lead to daily tiredness,Achievement losses and depressive detunings. A treatment with medicines is nearly always possible.

DSPS (Delayed Sleep phase of syndromes)

Narkolepsie is a syndrome sleep compelled by four characteristic ranges, their prevailing symptom a diseased increased day sleepyness as well as by trip events („trigger sleep “)or loss of muscle control (Kataplexie) are. Furthermore often the sleep phases are in their order changed, so that it can come too „hypnagogen hallucinations “and too „sleep paralysis “. Neurobiologically the Narkolepsie a genetic defect lies inReceptor for Orexin (S. o.) at the basis.

Sleep paralysis occurs also with healthy humans sometimes when waking up. Loosening the nerve blockade runs off then in wrong order, so that first the sensory nerves become de-energised and then only the motor nerves „“.In this condition and feel humans hear everything, can however nothing say, not move, also the respiration not accelerate. It is reported by a restraining feeling of complete powerlessness.

Such a situation steps also sometimes with insufficiently anaesthetized patientsduring an operation up. Some forms of the coma are to be likewise felt by concerning in such a way, also there is report of drug consumption ducks over such experiences.

Sleep withdrawal

sleep withdrawal is the intended and/or. inadvertent preventing of sleeping, D. h. the suppression of the sleep pressure.

Rats, which were prevented to research purposes by force from the sleep, died finally. Before its death a disturbance of the maintenance of the Körpertemperatur (thermal regularization) showed up. In antique Rome is to have been killed king Perseus of Macedonia as a prisoner by sleep withdrawal.In the year 1965 the 17-jährige set up American pupils Randy Gardner a world record, by not sleeping 264 hours (thus 11 days). Independent observers pursued his attempt. In Germany attempts were likewise employed to sleep withdrawal and its effects, whereby itselfvery negative consequences showed. After 24 hours were very easy the test subjects to provoke and reacted already to the smallest movement aggressively. After 65 hours a woman began to see spin weaving when washing on arms and in the face and trieddespaired to remove it. Another woman weighted that their hat was too close and presses, although it did not carry.

Under certain circumstances controlled sleep withdrawal can be anti-depressive effective.


  • Alexander Borbély: Sleep. Modern sleep research, sleep stages, regularization of the Schlafes,Sleep with the baby, sleep at the age, short and, dreams, sleep disturbances, Stimulantien and sleeping drug, sleep of animals, sleep and learning, risks of the lack of sleep. Fischer, Frankfurt A.M. 2004, ISBN 3-596-15561-4. Expenditure for Internet of the version of 1988 as the secret of the sleep. New ways and realizations of the research.
  • Sophie de Sivry, Philippe Meyer: The art of the sleep. A small social, symbolic, medical, poetic and affectionate history of the sleep. 2. Aufl. Brandstätter, Vienna and others 1997, ISBN 3-85447-732-5
  • H. Schulz (Hrsg.): Manual sleep medicinefor training, hospital and practice (German society for sleep research and sleep medicine). 2 Bde. + CDROM: Digital Atlas of the sleep disturbances. Ecomed, Landsberg/Lech 2001ff.
  • Peter Clarenbach (Hrsg.): Schering encyclopedia sleep medicine. 2. Aufl. MMV, medicine Verl., Munich 1998, ISBN 3-8208-1334-9
  • Hans Rudolf Mächler: ThoseBeginnings of modern sleep research. Juris, Zurich 1994, ISBN 3-260-05373-5
  • Peretz Lavie: The wondrous world of the Schlafes. Discoveries, dreams, phenomena. Dtv, Munich 1999, ISBN 3-423-33048-1
  • January fount, Ulrich Kraft: Learn in the sleep - no dream.In: Spektrum der Wissenschaft, November 2004, 44-51, ISSN 0170-2971

see also

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